No Arthurian legend would be complete without Excalibur. It is sometimes attributed with magical powers or associated with the rightful sovereignty of Great Britain. Sometimes Excalibur and the Sword in the Stone (the proof of Arthur's lineage) are said to be the same weapon, but in most versions they are considered separate. The sword was associated with the Arthurian legend very early. In Welsh, the sword is called Caledfwlch.

King Arthur is a legendary British leader who, according to medieval histories and romances, led the defence of Britain against the Saxon invaders in the early 6th century. The details of Arthur's story are mainly composed of folklore and literary invention, and his historical existence is debated and disputed by modern historians.